Refactor FFmpegURLProtocol code from FFmpegDemuxer into BlockingUrlProtocol.

media/media.gyp

Index: media/media.gyp
diff --git a/media/media.gyp b/media/media.gyp
index b0c2bdf3a072c3cca2f803ebb947d083aa5fad42..eee4b1176d4c11a45c7d5f10284a2935a62e9173 100644
--- a/media/media.gyp
+++ b/media/media.gyp
@@ -255,6 +255,8 @@
         'filters/audio_renderer_algorithm.h',
         'filters/audio_renderer_impl.cc',
         'filters/audio_renderer_impl.h',
+        'filters/blocking_url_protocol.cc',
+        'filters/blocking_url_protocol.h',
         'filters/chunk_demuxer.cc',
         'filters/chunk_demuxer.h',
         'filters/decrypting_audio_decoder.cc',
@@ -367,6 +369,8 @@
             'filters/audio_file_reader.h',
             'filters/chunk_demuxer.cc',
             'filters/chunk_demuxer.h',
+            'filters/blocking_url_protocol.cc',
+            'filters/blocking_url_protocol.h',
             'filters/ffmpeg_audio_decoder.cc',
             'filters/ffmpeg_audio_decoder.h',
             'filters/ffmpeg_demuxer.cc',
@@ -649,6 +653,7 @@
         'ffmpeg/ffmpeg_common_unittest.cc',
         'filters/audio_renderer_algorithm_unittest.cc',
         'filters/audio_renderer_impl_unittest.cc',
+        'filters/blocking_url_protocol_unittest.cc',
         'filters/chunk_demuxer_unittest.cc',
         'filters/decrypting_audio_decoder_unittest.cc',
         'filters/decrypting_video_decoder_unittest.cc',
@@ -715,6 +720,7 @@
             'base/test_data_util.cc',
             'base/test_data_util.h',
             'ffmpeg/ffmpeg_common_unittest.cc',
+            'filters/blocking_url_protocol_unittest.cc',
             'filters/chunk_demuxer_unittest.cc',
             'filters/ffmpeg_audio_decoder_unittest.cc',
             'filters/ffmpeg_demuxer_unittest.cc',